1、SSPC-Paint 41February 1, 20081SSPC: The Society for Protective CoatingsPainT SPECiFiCaTiOn nO. 41Moisture-Cured Polyurethane Primer or intermediate Coat, Micaceous iron Oxide Reinforced, Performance-Based1. ScopeThis specification contains performance requirements for a moisture-cured aromatic polyu
2、rethane coating with a thermoset binder and micaceous iron oxide pigment reinforcement.2. Description2.1 This coating is a single-package moisture-cured polyurethane coating characterized by the presence of free isocyanate groups capable of reacting with atmospheric mois-ture in order to form a soli
3、d film.2.2 Coatings meeting the requirements of this specifica-tion are generally suitable for exposures in environmental zones 1A (interior, normally dry), 1B (exterior, normally dry), 2A (frequently wet by fresh water excluding immersion), 2B (frequently wet by salt water, excluding immersion), 3B
4、 (chemical exposure, neutral) and 3C (chemical exposure, alkaline). Primer/intermediate coat systems described in this standard meet the performance requirements of Section 7.4 of SSPC-Paint 40 (including Environmental Zone 2C-Fresh Water Immersion).2.3 This coating is intended for spray application
5、 according to manufacturers instructions, with allowance for small area touch-up by brush (see Note 11.1) either directly to a steel substrate, or over itself or a compatible primer such as SSPC-Paint 40 or other primers recommended by the coating manufacturer. 3. Referenced Standards3.1 The latest
6、issue, revision, or amendment of the refer-enced documents in effect on the date of invitation to bid shall govern unless otherwise specified. Those documents marked with an asterisk (*) are referenced only in the Notes or the Appendix, which are not requirements of this specification.3.2. If there
7、is a conflict between the requirements of any of the cited reference documents and this specification, the requirements of this specification shall prevail.3.3 SSPC STanDaRDS anD JOinT STanDaRDS: Guide 13 Guide for the Identification and Use of Industrial Coating Materials in Computerized Product Da
8、ta-bases PA 2 Measurement of Dry Coating Thick-ness with Magnetic GagesPaint 40 Zinc-Rich Moisture Cure Poly-urethane Primer, Performance BasedSP 1 Solvent CleaningSP 5/NACE No. 1 White Metal Blast Cleaning3.4 aSTM inTERnaTiOnaL STanDaRDS:1D 185 Standard Test Methods for Coarse Particles in Pigments
9、* D 562 Standard Test Method for Consistency of Paints Measuring Krebs Unit (KU) Viscosity Using a Stormer-Type ViscometerD 714 Standard Test Method for Evaluating Degree of Blistering of Paints* D 1475 Standard Test Method for Density of Liquid Coatings, Inks, and Related ProductsD 1640 Standard Te
10、st Methods for Drying, Curing, or Film Formation of Organic Coatings at Room TemperatureD 1654 Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments* D 2369 Standard Test Method for Volatile Content of Coatings* D 2371 Standard Test Method for Pigment
11、 Content of Solvent-Reducible PaintsD 2794 Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact)D 4417 Standard Test Methods for Field Measurement of Surface Profile of Blast Cleaned SteelD 4541 Standard Test Method for Pull-Off Strength of Coatings Usi
12、ng Portable Adhesion Testers1 ASTM International, 100 Barr Harbor Drive, West Conshohock-en, PA 19428-2959. Standards available online from http:/www.astm.org.SSPC-Paint 41February 1, 20082D 5894 Standard Practice for Cyclic Salt Fog/UV Exposure of Painted Metal, (Alternating Exposures in a Fog/Dry
13、Cabinet and a UV/Condensation Cabinet)3.5 aMERiCan naTiOnaL STanDaRDS inSTiTUTE (anSi) STanDaRD:2ANSI Z129.1 Hazardous Industrial ChemicalsPrecautionary Labeling4. Composition Requirements4.1 The manufacturer is given wide latitude in the selection of materials and manufacturing processes. 4.2 Pigme
14、nt Requirement4.2.1 Micaceous iron oxide is a required pigment compo-nent in this coating (see Note 11.2 for typical formulation percentage ranges). The manufacturer shall provide informa-tion on the micaceous iron oxide content on the product data sheet, or as required by the purchaser.4.2.2 Option
15、al pigment components include extenders, tinting colors and suspension control agents.4.3 Resin Requirement: The resin used in the coating shall be a polyisocyanate-based product that cures through a chemical reaction with atmospheric moisture. Use of other resins or modifiers shall be limited to pr
16、oducts necessary for formula ingredient compatibility and to improve recoating properties. See Note 11.3 for information on VOC content, and Note 11.4 for information on modifying resins.4.4 analytical Test Data: If mutually agreed upon by purchaser and supplier, the coating manufacturer shall provi
17、de certificates of analysis for coating batches qualified by inde-pendent testing to meet this standard, including petrographic analysis of the percentage of lamellar particles present in the micaceous iron oxide pigment.5. Standard Testing Conditions 5.1 TEST PanELS: The hot rolled steel test panel
18、s shall conform to ASTM A 572. Panel size shall be 100 mm x 150 mm x 3.2 mm (4 inch x 6 inch x 1/8 inch). Test panels shall be solvent cleaned in accordance with SSPC-SP 1 prior to blast cleaning. The test panels shall be blast cleaned in accordance with SSPC-SP 5. The blast profile shall be 44 to 5
19、7 micrometers (1.75 to 2.25 mils) as measured in accordance with ASTM D 4417, Method C.2American National Standards Institute, 1819 L Street, NW, Suite 600, Washington, DC 20036. Standards available online from www.ansi.org.5.2 aPPLiCaTiOn: The coating shall be spray applied as a single coat in acco
20、rdance with recommendations on the manufacturers product data sheet. The coating shall show no streaking, running, sagging, or other defects during application or while drying.5.3 DRY FiLM THiCKnESS: The dry film thickness (DFT) on the test panels shall meet the manufacturers written recom-mended ra
21、nge. The DFT shall be measured in accordance with SSPC-PA 2, Appendix 5. 5.4 CURE: The primer shall be dried and cured in accor-dance with manufacturers written recommendations. Before any testing, all coated panels shall be aged for a minimum of 7 days in an environment with a minimum relative humi
22、dity of 50%, and at a temperature of 23 2 C (73.5 3.5 F), as described in paragraph 5.1 of ASTM D 1640.5.5 SCRiBinG: Scribe two parallel lines on the face of the coated panels so as to expose the underlying metal before testing. The lines shall be at least 2.5 cm (1 inch) from the edge, the top, and
23、 the bottom of each panel and at least 5 cm (2 inches) from each other. Each scribe shall be 6 cm (2.4 inches) long. The scribes may run vertically or at an angle across the face of the panel. Follow the scribe-making procedure described in ASTM D 1654.5.6 BaCKS anD EDGES: Coat and seal all edges an
24、d the back side of each panel with a coating or tape that will provide the necessary protection to these surfaces.6. Requirements of Liquid Coating6.1 MiXinG: The coating shall be mixed and dispersed to produce a product that is uniform, stable, free from grit, and in conformance with the requiremen
25、ts of this specification6.1.1 The single-component coating shall be capable of being dispersed under mechanical agitation to a smooth, uniform consistency and shall not show any objectionable properties in the mix. 6.1.2 After mixing and filtering through a standard 60 mesh screen in accordance with
26、 ASTM D 185, the amount of coarse particles and skins retained shall not exceed 0.5% by weight (see Note 11.5).6.2 STORaGE LiFE: The coating shall exhibit no curdling, gelling, gassing, or hard caking after being stored unmixed for a minimum of six months from date of delivery in a tightly sealed, u
27、nopened container at a temperature of 10 to 32 C (50 to 90 F).6.3 WORKinG PROPERTiES: The mixed coating shall spray easily and show no signs of streaking, running, sagging, or other objectionable features when applied according to SSPC-Paint 41February 1, 20083the manufacturers product data sheets.
28、Notes 11.6 and 11.7 provide additional information on adhesion testing and quality assurance tests. 7. Laboratory Physical Tests of applied Films7.1 PRiMER aDHESiOn TO SUBSTRaTE: Apply the primer to three panels in accordance with Sections 5.1 through 5.4. Test adhesion using an adhesion tester with
29、 a self-aligning pulling mechanism as described in ASTM D 4541. Report the type of adhesion tester employed. Perform three pulls per panel. The minimum adhesion value of the primer to the substrate for each pull shall be 4.1 MPa (600 psi). In the case of adhesive failure below 4.1 MPa (600 psi), the
30、 pull test shall be repeated. The instrument used to verify compliance to this standard shall be of the same type used to perform the initial testing.7.2 inTERMEDiaTE COaT aDHESiOn TO PRiMER: If this coating is to be used as an intermediate coat over itself or another primer, apply the intermediate
31、coat to three primed panels prepared in accordance with Sections 5.1 through 5.4. Use only primers identified as compatible by the intermediate coat manufacturer. Test adhesion using an adhesion tester with a self-aligning pulling mechanism as described in ASTM D 4541. Report the type of adhesion te
32、ster employed. Perform three pulls per panel. The minimum adhesion value of the intermediate coat to the primer for each pull shall be 4.1 MPa (600 psi). In the case of adhesive failure below 4.1 MPa (600 psi), the pull test shall be repeated. The instrument used to verify compliance to this standar
33、d shall be of the same type used to perform the initial testing.7.3 DiRECT iMPaCT RESiSTanCE: The minimum impact resistance when measured in accordance with ASTM D 2794, shall be 6.8 Nm (60 inch-lb). Table 1 provides a summary of performance requirements for laboratory and accelerated testing.8. acc
34、elerated Laboratory Weathering Require-ments8.1 CYCLiC SaLT SPRaY/UV/COnDEnSaTiOn CaBinET: Triplicate panels prepared in accordance with Section 5 shall be exposed in a cyclic test cabinet in accordance with ASTM D 5894 for 1500 hours. 8.1.1 Rust Evaluation: After the specified exposure time, each r
35、eplicate panel shall have no rusting of the coated portion (a rust rating of 10 per SSPC-VIS 2). Moderate rusting in the scribe mark is permissible and resulting staining shall be ignored. Strips 6 mm (1/4 inch) wide along the edges of the panel shall be ignored.8.1.2 Blister Evaluation: After the s
36、pecified exposure time, there shall be no blistering of the coated portion (a rating of 10 per ASTM D 714).8.1.3 Scribe Evaluation: After the specified exposure time, the undercutting from the center of the scribe, measured at any point along the scribe, shall be a maximum of 4 mm (3/16 inch), a rat
37、ing of 5 per Table 1 of ASTM D 1654. Moderate rusting in the scribe mark is permissible and resulting staining should be ignored. TaBLE 1PERFORManCE REQUiREMEnTSTestnumber of SpecimensExposure TimeRust Rating, SSPC-ViS 2 Blister Rating, aSTM D 714Scribe Undercutting, aSTM D 1654Corrosion after Expos
38、ure in Cyclic Accelerated Test Cabinet (ASTM D 5894)3 1500 hours All 10 All 10Moderate rust in scribe, maximum undercutting 4 mm (ASTM rating of 5)Minimum Acceptable Rating TestPrimer adhesion 3 panels,3 pulls per panel-4.1 MPa (600 psi) for any pullASTM D 4541, Methods II, III, IV or VIntermediate
39、Coat Adhesion to Primer3 panels3 pulls per panel-4.1 MPa (600 psi)for any pullASTM D 4541, Methods II, III, IV or VDirect Impact Resistance3 -68 Nm (60 inch-lb).ASTM D 2794SSPC-Paint 41February 1, 200849. Labeling 9.1 Labeling shall conform to ANSI Z129.1. 9.2 Technical data shall be provided for at
40、 least all data elements categorized as “essential” in SSPC-Guide 13.10. Disclaimer10.1 While every precaution is taken to ensure that all information furnished in SSPC standards and specifications is as accurate, complete, and useful as possible, SSPC cannot assume responsibility nor incur any obli
41、gation resulting from the use of any materials, coatings, or methods specified herein, or of the specification or standard itself.10.2 This specification does not attempt to address prob-lems concerning safety associated with its use. The user of this specification, as well as the user of all produc
42、ts or practices described herein, is responsible for instituting appropriate health and safety practices and for ensuring compliance with all governmental regulations.11. notesNotes are not requirements of this specification. 11.1 aPPLiCaTiOn: Moisture-cure polyurethane coatings are preferably appli
43、ed by spray directly to steel substrates, but may be brushed on small areas for touch-up or to fill in irregularities.11.2 PiGMEnT: The typical micaceous iron oxide content for these coatings ranges from 15 to 35% by weight of nonvola-tile components.11.2.1 Micaceous iron oxide pigment is incorporat
44、ed into coatings for the purposes of improved film hardness, decreased film porosity and viscosity control. It may also provide improved adhesion to steel substrates, and superior intercoat adhesion properties. Micaceous iron oxide can impart a measure of film reinforcement while relieving stresses
45、that can be developed in the binder. Optimally, the pigment provides a better barrier to the effects of ultraviolet weathering exposure.11.2.2 Blends of micaceous iron oxide and aluminum pigments are used in various coating formulations for reasons of improved ultraviolet light and water resistance
46、where extended periods of exterior exposure are anticipated prior to application of topcoats.11.3 VOC COnTEnT: Federal limits for VOCs in industrial maintenance coatings were published in 1998 and may be found at http:/www.epa.gov/ttn/atw/183e/aim/aimpg.html#RULE. These limits apply to the coating a
47、t the time of application after thinning according to the manufacturers recommendations. Many state and local governments and/or air quality manage-ment areas have more stringent VOC regulations than those in the federal rule. Information on the VOC content of each container before mixing or thinnin
48、g is found on the container label and in the manufacturers safety data sheet. The coating manufacturers product data sheet usually provides informa-tion on the total VOC content of a coating after mixing and any recommended thinning. 11.4 MODiFYinG RESinS: Other resins or modifiers are typically les
49、s than 15% of total resin content. 11.5 SiEVE SiZES: While Section 6.1.2 requires use of standard 60-mesh screen, the contracting parties may agree upon alternate screen sizes for new technology coatings. 11.6 TOPCOaT aDHESiOn: If desired, an adhesion test may be performed to determine adhesion between this coating and a compatible topcoat. To test for adhesion, prepare three panels in accordance with Sections 5.1 through 5.3. Apply a compatible topcoat and cure as recommended by the topcoat manufacturer. The thickness of the topcoat shall conform to the manufacture
